Method of labeling containers



Dec. 16, 1952 l... M. PERRY 2,621,323

METHOD OF LABELING CONTAINERS Filed April 19, 1951 Irwenfoat- L'Zqyd Mleifiigg, Q9 M M, KW 415, ww fliigls Patented Dec. 16,1952

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METHOD OF LABELING CONTAINERS Lloyd M. Perry, Nashua, N. H, assignor to Nashua Corporation, a corporation of Massachusetts Application April 19, 1951, Serial No. 221,887

This invention relates to securing labels by means of heat-activated adhesive to cans, bottles, jars and the like. It finds a particular application in connection with the use of an adhesive of the kind described in my Patent No. 2,462,029, February 15, 1949, which is rendered adhesive only when exposed to a relatively high tempera-- ture, but which will remain tacky for a substantial period of time when subsequently cooled to a considerably lower temperature. The general object is to provide a method for securing such perfect adhesion of the label to the container as to obviate the possibility of later development of first briefly to describe the machine shown in Fig. 1 of the drawing. There is there shown, more or less diagrammatically, the principal elements of a labeling machine for applying adhesively coated labels. In general the machinei's of known form, being essentially similar to that shown and described in the patent to Von Hofe 2,525,741, October 10, 1950, to which reference may be made for details of construction, but it is slightly modified to permit the practice therewith of the present method.

In the machine a Wormlike rotating member 26 serves to arrange the containers 20 in spaced relation on a traveling conveyor 24 and the labels L are applied individually to successive containers of the advancing file and smoothed out thereon. For the purposes of the present description it will be sufficient to note that there is a stack of labels C in a suitable container from which successive labels L are taken by means of a pickup mechanism or transfer roll D and delivered to an activating and applying drum E. The transfer mechanism D is a suction roll which picks up the top label L of the stack, and, rotating clockwise in the figure, brings its leading end against one of the projecting bars 55 on the drum E. The suction mechanism of the roll D then goes out of action and a suction mechanism on the drum E 2 Claims. (Cl. 216-452) becomes effective to hold the label to the surface of the drum to be carried around with it in its counterclockwise rotation. The adhesive coating on the label is outward at this stage. The drum isheated and in the course of the travel of the roll to bring the label L to the six oclock position in the figure the coating is rendered adhesively tacky.

At the six oclock position the leading end of the label L behind one of the ribs 56 is opposite a container 2!] and at this point the suction is released on this portion of the label and posi-' tive" pressure applied, causing-the leading end of the'l'abel to make contact with the container andadhere theretoj -The container then continues to the right, secured by its'leading end and'with the rest of the label traveling as shown, there-' after to be rolled down into contact with the container by pressure progressively applied from its leading and attached' end. What has just been described is not new.

It has been found that when labels are applied in this manner minor blisters or welts' may develop in the completed work. In the light of the localized areas of imperfect adhesion. This may be demonstrated by securing a label in the manner just described and then wetting it, after which blisters will appear. It may be surmised that the aggressively adhesive tack of the coating and the relative inflexibility of the dry paper permit small areas of imperfect adhesion, imperceptible as such, the label appearing perfectly smooth and close-fitting, but which permit the paper to bulge when it expands when wet.

The phenomenon of shrinkage which occurs when wetted paper is allowed to dry is well known. It is utilized, for example, when a paper dust cover is secured to the back of a picture frame. It was therefore inferred that if the label could be applied damp and molded to the container in that condition, not only would better adhesion be secured initially, but the shrinkage of the label would tension it tightly in its position. However, it would be impractical to wet the labels initially and before application to the containers, as they would become unmanageable and could not be handled either in an automatic machine as disclosed, or practically speaking, in any other manner.

In accordance with the invention therefore the label is activated and applied dry to the container, being adhered thereto over all or a portion of its area. It is then moistened with water or steam, which is permitted to act on the paper for a brief period of time after which it is pressed and smoothed out into firm contact with the container. The adhesive should remain tacky to permit more or le s shifting of the label, as necessary, in connection with this final'pressing of it into position, but when a suitable adhesive of the type described in my patent referred to is used this offers no difliculty.

Referring again to Fig. 1 of the drawings, there is there shown a sprayer head S apposing conveyor 24 at a point in the offtake side of the drum E and at suitable intervals as a container 20 with its trailing label passes this sprayer, the latter is operated to moisten the label. It will be noted that in the drawing the conveyor 24 is shown broken away immediately to the right of the sprayer head, indicating that the travel of the containerwith its moistened label may be continued for such brief period oftime as to permit the proper absorption of the water into the paper to result in effective tempering of the paper. The container with its now expanded label still trailing now passes between an abutment wall 32 and the apposed run of a driven belt 29, which run moves toward the right in the figure. This will cause rotation of the container clockwise, winding up the label around the container while pressing or ironing it out into firm contact therewith. On dryingof the label and shrinkage of the-paper a perfectly tight fit is obtained which will not bealtered by any subsequent expansion of the paper due to exposure of the labeled container to humid conditions.

In Fig. 2 I have shown an appliance by'the aid of which the method might be practiced by hand, that is, not by a fully automatic machine. A label may be activated by heating in any suitable heater and applied to the container by hand approximatelyas it would beapplied if no further operation were contemplated. The exterior of the label may then be moistened and the paper allowed to temper. The appliance shown may then be used to iron out .the label and correct and perfect its attachment to the container. In the device shown two rolls 200 may be arranged to form a sort of cradle into which a cylindrical container may be introduced, resting on its cylindrical surface. The spacingofthe rolls 200, herein shown for simplicity as fixed, is adapted to the size of the container for which the appliance is used. Opposed is a centrally positioned top roll 202, herein shown as mounted in vertical slots 204 to permit it to be raised when the container is inserted and providing when it is in position for holding the container against the bottom rolls 200 with adequate pressure to provide traction of the surfaces of the latter rolls on the container. If one or both of the rolls 200 is. positively driven, as indicated by the showing of a. hand crank 206 on one of them, the container will be rotated and the label thereon ironed out. If the moistemng step is kept one or more of the containers ahead of the rolling step the labels will be suitably tempered and expanded so'that they may be to a greater or less extent repositioned on the containers and will firmly adhere thereafter throughout their entire area.

I claim:

1. The method of attaching labels to containers by means of a heat-activatable adhesive coated on the back of the label throughout its area which comprises activating the coating to cause itto become adhesively tacky, then securing the label to the container by such adhesive in'at least a portion of its area, thereafter humidifying the body of the label to soften and to provide for expansion of the same and then pressing the label into intimate contact with the container throughout the entire area of the former while the coating is adhesively tacky.

2. The method of attaching labels to containers by means of a heat-activatable adhesive coated onthe back of the label throughout its area which comprises activating the coating to cause it to become'adhesively tacky, then securing the label to the" container by such adhesive along an edge portion thereof, thereafter humidifying the body of the label to soften and to provide for expansion of the same and then pressing the label throughout its entire area into intimate contact with the container by a wiping pressure proceeding from the secured edge while the coating is adhesively tacky.

LLOYD M. PERRY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,329,696 Blackstone Feb. 3, 1920 2,238,436 Von Hofe Apr. 15, 1941 2,525,741 Von Hofe et al. Oct. 10, 1950 

